#3 Seth Rollins
The Undertaker has never squared off against Seth Rollins in singles competition despite facing two-thirds of the Shield previously. "The Architect" is a versatile performer and delivers tremendous performances on a weekly basis.
Despite being directionless in 2017, Rollins has finally found himself in a pleasant spot. Regardless of what happens tonight, "The Man" is heading for greater things in 2018.
Therefore, if the 31-year old Superstar is looking to reclaim the main event spot, then a showdown with the Undertaker could push him to the limits.
The feud, the booking, and the matches could be terrific; elevating Rollins to another level. The Undertaker's physical condition has depreciated his in-ring value, but the "King Slayer" could carry him to a fantastic match.